World map shows the changing center of the world economy over the last 2000 years. Since the 1950s and the rise of Japan the economic center moved east again. Now China is pulling this center even further east. Source: https://t.co/rXM1CN0Hfdpic.twitter.com/GgM3vv7EJf
The physicist Arnold Sommerfeld was the first person to use the contour integral sign ∮ in his 1917 paper "Drude's dispersion theory from the point of view of Bohr's model and the constitution of H₂, O₂ and N₂" pic.twitter.com/jiX0Dho5pI